This invention pertains generally to electrical connectors and specifically to a printed circuit card (PCC) receptacle and an arrangement for easily and quickly attaching and detaching card guides to PCC connectors to form the receptacle.
The use of printed circuit cards in the field of electronics has become wide spread as a result of their convenience, flexibility, minimal space requirements and reduced production costs. The predominance of printed circuit cards is due in great part to the ease and speed with which circuit card components are connected to other system components merely by plugging the card into a PCC connector. The PCC connector is usually an oblong block of electrical insulating material having a plurality of electrical conductors each with a pin and contact portion. The conductors are embedded in the block of insulating material and arranged in columnar fashion with the contact portions along or in an elongated aperture or card receiving slot formed in the block, the pins protruding laterally from the block. A printed circuit card having circuit contacts disposed along an edge thereof is received into the slot of the connector block. As the edge of the PCC is received in the connector slot, the contact portions of the conductors in the slot and the circuit contacts on the PCC are pressed together to make electrical contact with one another. The pin portions of the conductors are wired or otherwise connected to other system components, e.g., via other connector pins, and the circuit contacts are connected to components on the card; therefore, the mere insertion of the card in the connector slot completes the various electrical connections between the card and other system components.
The PCC is commonly guided into place in the connector by a pair of card guides having slotted guideways, each guide being located at or near one end of the connector and extending outwardly from the end in a plane with the elongated aperture of the connector to receive and guide one edge of the card. The guides may also serve as a support for the PCC once the card is inserted into the connector.
It is common practice for electronic equipment manufacturers to establish at least one standard size for printed circuit cards and their associated mounting and interconnection hardware, and then make or purchase edge connectors having card guides already attached at either end thereof for use with printed circuit cards of the standard size. For standard size PCC's and connectors, one guide is required at each end of each connector. This facilitates rapid assembly of the electronic equipment since most of the PCC's are of the standard size. If larger than standard PCC's are used, then two or more standard connectors may be combined so that the card receiving slots are aligned longitudinally to accommodate the larger printed circuit card. In the latter case, only one card guide is required at either of the outboard ends of the aligned assembly of connectors. It is necessary, therefore, to remove the unneeded central card guides. Thus, it is important that the guides be easily and quickly removable. Many commercially available card guides are attached to connectors or the frames which hold the connectors by means of screws or other types of fasteners so that hand tools are required whenever the card guides are attached or removed. The use of hand tools imposes a burden on the equipment manufacturer since this is cumbersome and time consuming, particularly in view of substantial number of connectors utilized in modern equipment and the difficulty of maneuvering tools in the congested equipment spaces where the connectors and PCC's are located.
Some prior art guides can be attached and detached without the use of tools. These guides, however, have an inherent disadvantage in that they often fail to provide a firm support for the printed circuit cards and they are not easily and quickly detachable from the connectors. For example, one type of card guide is wedged into an aperture and held in place merely by a force fit. Such a means of attachment is undesirable since the card guide can be easily dislodged and therefore does not provide a reliable support for the printed circuit cards. Another prior art card guide is held in place in an aperture through the use of dimples located on the card's periphery so that once the card guide is in place it becomes very difficult to release.
Electronic equipment is subject to environmental stress (e.g., vibration) during operation which tends to cause printed circuit cards to work loose from their receptacles, resulting in open electrical circuits. Some prior art receptacles having a PCC gripping means have failed to provide means for locking the PCC in place to prevent migration of the card out of the connector.
It is, therefore, a broad object of the present invention to provide an improved printed circuit card receptacle.
It is another object of the present invention to provide an improved printed circuit card receptacle including a connector for receiving a pluggable element, and a card guide attached to the connector for guiding the pluggable element into the connector and holding the pluggable element therein.
An additional object of the invention is to provide a new and improved printed circuit card guide and connector assembly which permits card guides to be attached to and detached from connectors quickly, easily and conveniently without the use of tools.
It is still another object of the invention to provide an improved pluggable element receptacle of a standard size having a facile means for converting the receptacle to receive pluggable elements larger than the standard size.
It is a further object of the present invention to provide a new and improved printed circuit card guide and connector assembly which provides a firm and rigid support for the printed circuit card.